Nozzle arrangement with a thermal actuator incorporating heat sinks

Abstract

The present invention relates to a nozzle arrangement for an inkjet printer. The nozzle arrangement includes a substrate assembly defining an inlet channel. A nozzle chamber wall and a roof wall are collectively positioned on the wafer substrate to define a nozzle chamber in fluid communication with the inlet channel. The roof wall defines an ejection port in fluid communication with the nozzle chamber. A thermal actuator is mounted to the substrate assembly and extends into the nozzle chamber to terminate in a free end. The thermal actuator includes a pair of actuating members spaced apart to form a gap and a heat sink assembly positioned in the gap. One of the actuating members is connected to an electrical supply so that differential expansion between the actuating members can cause movement of the free end and results in the ejection of ink in the nozzle chamber from the ejection port.

1. A nozzle arrangement for an inkjet printer, the nozzle arrangement comprising:
 a substrate assembly defining an inlet channel; 
 a nozzle chamber wall and a roof wall collectively positioned on the substrate assembly to define a nozzle chamber in fluid communication with the inlet channel, the roof wall defining an ejection port in fluid communication with the nozzle chamber; and 
 a thermal actuator mounted to the substrate assembly and extending into the nozzle chamber to terminate in a free end, the thermal actuator comprising a pair of actuating members spaced apart to form a gap and a heat sink assembly positioned in the gap, one of the actuating members being connected to an electrical supply so that differential expansion between the actuating members can cause movement of the free end and results in the ejection of ink in the nozzle chamber from the ejection port. 
 
   
   
     2. A nozzle arrangement as claimed in  claim 1 , wherein the heat sink assembly includes a pair of spaced apart heatsinks each extending between and making contact with the actuating members. 
   
   
     3. A nozzle arrangement as claimed in  claim 1 , wherein the substrate assembly includes a substrate, and the electrical supply is in the form of one or more CMOS layers positioned on the substrate. 
   
   
     4. A nozzle arrangement as claimed in  claim 1 , wherein the actuating members are of a resiliently flexible material. 
   
   
     5. A nozzle arrangement as claimed in  claim 1 , wherein the thermal actuator further includes an actuating arm that extends through an opening defined in the nozzle chamber wall and is connected to the paddle at the free end. 
   
   
     6. A nozzle arrangement as claimed in  claim 5 , wherein the nozzle chamber wall defines a re-entrant portion at the opening. 
   
   
     7. A nozzle arrangement as claimed in  claim 6 , wherein the substrate assembly further defines a channel that is positioned adjacent the re-entrant portion. 
   
   
     8. An inkjet printer including a plurality of nozzle arrangements as claimed in  claim 1 , the nozzle arrangements being arranged in rows and ranks with the elongate thermal actuators being arranged in parallel.